SpringBoot（5）SpringBoot2.0整合mybatis实现MySQL数据的增删改查并映射到wep层
SpringBoot（5）SpringBoot2.0整合mybatis实现MySQL数据的增删改查
（1）引入依赖
Mybatis的依赖
org.mybatis.spring.boot
mybatis‐spring‐boot‐starter
1.3.1
MySQL的依赖
mysql
mysql-connector-java
runtime
（2）引入Mybatis的配置文件，放在resources目录下，这个去官网找一找，抄一抄
（3）在application中配置读取Mybatis的配置文件,并配置和MySQL相关的配置，在这之前你要先设计你的数据库的字段，然后把你的数据库建立起来
spring.freemarker.suffix=.html
#设定freemarker读取文件的路径，默认也会到这里来找，，也可以设置别的路径
#spring.freemarker.template-loader-path=classpath:/templates
spring.freemarker.cache=false
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/wenda?useUnicode=true&characterEncoding=utf8&useSSL=false
spring.datasource.username=*****
spring.datasource.password=*******
mybatis.config-location=classpath:mybatis-config.xml到这里基本的配置都配置完了，接下来就实现数据库的访问
（4）持久层首先的当然是写DAO接口，在写DAO接口之前要先写一个与数据库表中内容对应的实现类，把表中每行的参数的get和set方法先写出来
package com.springboot.springboot.model;
public class User {
private Integer id;
private String name;
private String password;
private String salt;
private String head_url;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getSalt() {
return salt;
}
public void setSalt(String salt) {
this.salt = salt;
}
public String getHead_url() {
return head_url;
}
public void setHead_url(String head_url) {
this.head_url = head_url;
}
public User(){
}
public User(String name){
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String userDescription(){
return "This is "+ name;
}
}然后DAO的接口，
package com.springboot.springboot.dao;
import com.springboot.springboot.model.User;
import org.apache.ibatis.annotations.*;
@Mapper
public interface userDAO {
//这个地方注意前后加空格，后面不注意的话可能就出错了
String TABLE_NAME = " user ";
String TABLE_FIELDS = " name, password, salt, head_url ";
String SELECT_FIELDS = " id " + TABLE_FIELDS;
//增
@Insert({"insert into ", TABLE_NAME,"(",TABLE_FIELDS,
") Values(#{name}, #{password}, #{salt}, #{head_url})"})
int addUser(User user);
//查
@Select({"select ",SELECT_FIELDS,"from",TABLE_NAME, "where id=#{id}"})
User selectById(int id);
//改
@Update({"update",TABLE_NAME,"set password = #{password} where id = #{id}"})
void updatePassword(User user);
//删
@Delete({"delete from",TABLE_NAME,"where id = #{id}"})
void deleteUserById(int id);
}这里用的是注解的方式实现的
当然还可以编写.XML文件，在里面写数据库语句，然后在DAO接口中去对应的调用
如我现在写了一个：
question
id, title, content, user_id, created_date, comment_count
然后对应的DAO为：
//使用XML的方式完成数据库的操作
List selectLatestQuestions(@Param("user_id") int userId, @Param("offset") int offset,
@Param("limit") int limit); 这种实现方式注意的是要对应好
（5）测试类，测试好不好用
package com.springboot.springboot;
import com.springboot.springboot.dao.questionDAO;
import com.springboot.springboot.dao.userDAO;
import com.springboot.springboot.model.Question;
import com.springboot.springboot.model.User;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.jdbc.Sql;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.Date;
import java.util.Random;
//@RunWith(SpringRunner.class)
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
@Sql("/init-schema.sql")
public class InitDatabaseTests {
@Autowired
userDAO uDAO;
@Autowired
questionDAO qDAO;
@Test
public void initDatabase() {
Random random = new Random();
for(int i=0; i<11; ++i){
User user = new User();
user.setHead_url(String.format("http://images.nowcoder.com/head/%dt.png", random.nextInt(1000)));
user.setName(String.format("USER%d",i));
user.setPassword("");
user.setSalt("");
uDAO.addUser(user);
user.setPassword("XXX");
uDAO.updatePassword(user);
Question question = new Question();
question.setCommentCount(i);
Date date = new Date();
date.setTime(date.getTime() + 100*3600*i);
question.setCreatedDate(date);
question.setUserId(i+1);
question.setTitle(String.format("Title%d",i));
question.setContent(String.format("dgueuhdpwefpckaweni Content %d",i));
qDAO.addQuestion(question);
}
Assert.assertEquals("XXX",uDAO.selectById(1).getPassword());
uDAO.deleteUserById(1);
Assert.assertNull(uDAO.selectById(1));
System.out.println(qDAO.selectLatestQuestions(0,0,10));
}
}要是不想在所有的Mapper文件中都使用@Mapper注解
就在也就是你的启动或者测试文件中
使用MapperScan批量扫描所有的Mapper接口；
@MapperScan(value = "com.springbootdemo.springboot.mapper")
这样就完成了整个数据库的增删改查。
（6）那Web界面怎么去读取数据库中的数据呢？首先当然是编写service层
package com.springboot.springboot.service;
import com.springboot.springboot.dao.userDAO;
import com.springboot.springboot.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class userService {
@Autowired
userDAO uDAO;
public User getUser(int id){
return uDAO.selectById(id);
}
}然后写WEP层，就是Controller实现
package com.springboot.springboot.controller;
import com.springboot.springboot.model.Question;
import com.springboot.springboot.model.viewObject;
import com.springboot.springboot.service.questionService;
import com.springboot.springboot.service.userService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import java.util.ArrayList;
import java.util.List;
@Controller
public class homeController {
private static final Logger logger = LoggerFactory.getLogger(homeController.class);
@Autowired
questionService qService;
@Autowired
userService uService;
@RequestMapping(path = {"/user/{userId}","/index"},method = RequestMethod.GET)
public String userIndex(Model model, @PathVariable("userId") int userId){
model.addAttribute("vos",getQuestions(userId,0,10));
return "index";
}
@RequestMapping(path = {"/","/index"},method = RequestMethod.GET)
public String home(Model model){
model.addAttribute("vos",getQuestions(0,0,10));
return "index";
}
private List getQuestions(int userId,int offset, int limit){
List questionList = qService.selectLatestQuestions(userId,offset,limit);
List vos = new ArrayList<>();
for (Question question:questionList){
viewObject vo = new viewObject();
vo.set("question",question);
vo.set("user", uService.getUser(question.getUserId()));
vos.add(vo);
}
return vos;
}
} 中间为了方便写了一个freemaker与controller之间传递参数的函数，要不然都写在controller中显的乱七八糟
package com.springboot.springboot.model;
import java.util.HashMap;
import java.util.Map;
//用来传递freemarker与Controller之间的参数的
public class viewObject {
private Map objs = new HashMap();
public void set(String key, Object values){
objs.put(key, values);
}
public Object get(String key){
return objs.get(key);
}
}
对应的前端的页面
<#include "/header.html" encoding="UTF-8" parse=true>
<#include "/footer.html" encoding="UTF-8" parse=true>